Our present invention relates to a telescopable vacuum-cleaner suction pipe of the type in which an adjusting mechanism or actuator is provided to allow telescoping of an inner pipe into an outer pipe or an outer pipe over the inner pipe.
In telescopable vacuum-cleaner pipe assemblies, the suction pipe can be formed from an outer pipe and an inner pipe. The latter can have an axially-extending detent strip provided with recesses or the like and formed with at least one stop or blocking surface at each detent position while the outer pipe or a housing connected therewith is provided with a locking body displaceable toward the axis of the telescopingly-connected pipes and which engages in a selected one of the recesses to abut the stop surface thereof. The actuating device can move the locking body and a spring can be provided for maintaining the locked position.
The vacuum-cleaner suction pipe assembly of this type is disclosed in DE GM 297 19 437.2. The locking body of this system has a locking pin engageable in a detent hole of the inner pipe. Since these holes are pressed into the wall of the inner pipe, the lateral flanks of the detent holes tend to be inclined rather than perpendicular to the axis of the pipe and thus, when significant axial stress is applied between the inner and outer pipes, a camming action because of the inclination can give rise to a radial force component which can move the locking body out of the detent and release the lock.
It is, therefore, the principal object of the present invention to provide a telescopable vacuum-cleaner suction pipe assembly which has less of a tendency to self-release when axial stress is applied between inner and outer pipes.
Another object of the invention is to provide an assembly which is free from the drawbacks of the earlier system described and which, especially, provides a more reliable and is secure locking of the two pipes or tubes relative to one another.
It is also an object of the invention to provide a suction pipe assembly of the telescoping type whereby drawbacks of earlier systems are obviated.
These objects and others which will become apparent hereinafter are attained, in accordance with the invention by the use of an actuator which acts directly upon the locking body and is rotatable, i.e. pivotable or provided with an axis of rotation as in the case of an eccentric, and whereby the direct contact between the actuator and the locking body prevents the locking body from being cammed out of the detent recess, even when significant force is provided between the inner and outer pipes. More particularly, the surface which contacts the locking body of the actuator can be in line with the locking body and the axis about which the actuator can pivot or rotate so that the radial force, should it be produced, is entirely absorbed by the pivot or bearing of the rotatable body.
More particularly, the telescopable vacuum-cleaner suction pipe assembly can comprise:
an outer pipe;
an inner pipe telescopingly received in the outer pipe and provided with an axially extending row of detent recesses; and
an adjusting mechanism on the outer pipe having:
a sleeve surrounding the inner pipe,
a housing on the sleeve opening toward the row,
a locking body in the housing displaceable into and out of engagement with a selected one of the detent recesses,
an actuator rotatably mounted in the housing and bearing directly upon the body for locking the body in the selected one of the recesses in a locking position of the actuator and enabling movement of the body out of the selected one of the recesses in an unlocked position of the actuator, and
a spring acting upon the actuator and biasing the actuator into the locking position.
As a consequence, even upon the development of high axial forces and the possible application of substantial outward radial force to the locking body in the locked position, the latter position will be maintained since there is no force which will tend to rotate the actuator. With the system of the invention, there is no spring or the like between the rotatable actuator and the locking body and thus the locking body is mechanically fixed in its locked position without any yieldability until the rotatable actuator is displaced. The spring acting on the rotatable member merely serves to bias the latter into the locking position and does not itself absorb any of the locking force or yield to any radial force which can result from the application of large axial forces to the inner and outer pipes.
In one embodiment of the invention, the rotatable body or actuator is an actuating or locking rocker which can have a pair of axial projections forming slide bodies receivable in kidney-shaped openings in opposite walls of the housing. In that case, the projections not only slide in the openings but allow rotation of the rocker on the housing. A securely locked position is ensured by providing the engaging surfaces of the rocker and the locking body or member so that they are perpendicular to the radial force which may be generated and in line with a position of the slide block or projection which prevents the rocker from slipping out of the locked position. The rocker and locking body can then be clamped with a certain force in the locked position. Because the rocker can slide along the kidney-shaped openings, only a slight actuating pressure by the finger is required on the rocker to displace it into the unlocked position.
The force which must be applied for unlocking and relocking the assembly is relatively small, especially when the rocker is provided with a rounded actuating surface which can engage an inclined surface of the locking body.
According to another feature of the invention, the locking body itself may be pivotal on the sleeve and indeed the locking body can be formed as a pawl or lever in one piece with the sleeve and indeed the locking body can be relatively small, having a thickness of only several millimeters and can have a fixed position on the sleeve.
In another aspect of the invention, the actuator can be a rocker with a fixed axis about which the rocker can pivot.
In still another aspect of the invention, the actuator can be a rotatable eccentric which has the advantage that the position of the eccentric can be fixed with great precision within the housing and can, upon rotation, provide a free space into which the locking body can move upon displacement of the actuator from its locking position into the unlocked position.